title: Epidemiology of viral respiratory tract infections in an outpatient haematology facility.
abstract: Viral respiratory tract infections (VRTI) are an important cause of morbidity and mortality in haematology patients, particularly after haematopoietic stem cell transplantation (HSCT). The incidence, clinical presentation and outcome of symptomatic and asymptomatic VRTI in HSCT outpatient unit were prospectively evaluated during a single influenza season (January-March 2011). Pharyngeal swabs were performed at the first visit and if new symptoms were present. Molecular multiplex assay for 12 respiratory viruses was performed by the regional reference laboratory. Among 264 swabs from 193 outpatients, 58 (22 %) resulted positive for 61 viruses (influenza, n = 20; respiratory syncytial virus [RSV], n = 21; rhinovirus, n = 12; coronavirus, n = 4; adenovirus, n = 3; parainfluenza, n = 1). VRTI were detected more frequently in the presence of symptoms than in asymptomatic patients: 49 out of 162 (30 %) vs. 9 out of 102 (9 %), p < 0.001. Influenza-like illness syndrome (ILI) was significantly associated with a VRTI if compared to other presentations (42 %), while the European Centre for Disease Prevention and Control definition was not (30 %). Positive predictive value (PPV) of ILI for influenza was 17 %. Influenza and RSV peak periods were contemporary. Influenza prophylaxis was given to 25 patients following exposure. Low rate of progression from upper to lower respiratory tract infection (approximately 5 % for influenza and RSV), no nosocomial epidemics and no VRTI-related deaths were observed. VRTI are very frequent in high-risk haematology outpatients, but symptoms are aspecific and PPV of ILI is low. Symptoms of influenza and RSV overlap. Thus, microbiological diagnosis and contact preventive measures are crucial. Rather than universal influenza prophylaxis, prompt diagnosis and treatment of only documented infections could be pursued.
authors.affiliation: Division of Infectious Diseases, San Martino Hospital and University of Genoa, Largo R. Benzi, 10-16132, Genoa, Italy, m.mikulska@unige.it.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Mikulska
authors.forename: Valerio
authors.initials: V
authors.lastname: Del Bono
authors.forename: Nemo
authors.initials: N
authors.lastname: Gandolfo
authors.forename: Simone
authors.initials: S
authors.lastname: Dini
authors.forename: Alida
authors.initials: A
authors.lastname: Dominietto
authors.forename: Carmen
authors.initials: C
authors.lastname: Di Grazia
authors.forename: Stefania
authors.initials: S
authors.lastname: Bregante
authors.forename: Riccardo
authors.initials: R
authors.lastname: Varaldo
authors.forename: Andrea
authors.initials: A
authors.lastname: Orsi
authors.forename: Filippo
authors.initials: F
authors.lastname: Ansaldi
authors.forename: Andrea
authors.initials: A
authors.lastname: Bacigalupo
authors.forename: Claudio
authors.initials: C
authors.lastname: Viscoli
mesh_terms: D000553:Ambulatory Care / Q000379:methods*; D015331:Cohort Studies; D003428:Cross Infection / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D005260:Female; D019337:Hematologic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects; D006801:Humans; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D011446:Prospective Studies; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D012229:Rhinovirus / Q000302:isolation & purification